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Caesar cipher

Caesar cipher, is one of the simplest and most widely known encryption techniques. The transformation can be represented by aligning two alphabets, the cipher alphabet is the plain alphabet rotated left or right by some number of positions.

When encrypting, a person looks up each letter of the message in the 'plain' line and writes down the corresponding letter in the 'cipher' line. Deciphering is done in reverse.
The encryption can also be represented using modular arithmetic by first transforming the letters into numbers, according to the scheme, A = 0, B = 1,..., Z = 25. Encryption of a letter x by a shift n can be described mathematically as

Plaintext: wangle
 cipher variations: xbohmf ycping zdqjoh aerkpi bfslqj cgtmrk dhunsl eivotm fjwpun gkxqvo hlyrwp imzsxq jnatyr kobuzs lpcvat mqdwbu nrexcv osfydw ptgzex quhafy rvibgz swjcha txkdib uylejc vzmfkd

Decryption is performed similarly,

(There are different definitions for the modulo operation. In the above, the result is in the range 0...25. I.e., if x+n or x-n are not in the range 0...25, we have to subtract or add 26.)
Atbash Cipher

Atbash is an ancient encryption system created in the Middle East. It was originally used in the Hebrew language.
The Atbash cipher is a simple substitution cipher that relies on transposing all the letters in the alphabet such that the resulting alphabet is backwards.
The first letter is replaced with the last letter, the second with the second-last, and so on.
An example plaintext to ciphertext using Atbash:
 Plain: wangle Cipher: dzmtov

Baconian Cipher

To encode a message, each letter of the plaintext is replaced by a group of five of the letters 'A' or 'B'. This replacement is done according to the alphabet of the Baconian cipher, shown below.
```a   AAAAA   g    AABBA     m    ABABB   s    BAAAB     y    BABBA
b   AAAAB   h    AABBB     n    ABBAA   t    BAABA     z    BABBB
c   AAABA   i    ABAAA     o    ABBAB   u    BAABB
d   AAABB   j    BBBAA     p    ABBBA   v    BBBAB
e   AABAA   k    ABAAB     q    ABBBB   w    BABAA
f   AABAB   l    ABABA     r    BAAAA   x    BABAB
```

 Plain: wangle Cipher: BABAA AAAAA ABBAA AABBA ABABA AABAA

Affine Cipher
In the affine cipher the letters of an alphabet of size m are first mapped to the integers in the range 0..m - 1. It then uses modular arithmetic to transform the integer that each plaintext letter corresponds to into another integer that correspond to a ciphertext letter. The encryption function for a single letter is

where modulus m is the size of the alphabet and a and b are the key of the cipher. The value a must be chosen such that a and m are coprime.
Considering the specific case of encrypting messages in English (i.e. m = 26), there are a total of 286 non-trivial affine ciphers, not counting the 26 trivial Caesar ciphers. This number comes from the fact there are 12 numbers that are coprime with 26 that are less than 26 (these are the possible values of a). Each value of a can have 26 different addition shifts (the b value) ; therefore, there are 12*26 or 312 possible keys.
Plaintext: wangle
 cipher variations: xbohmf pbotin hbofev zborad rbodwl jbopst tbonkj lbozgr dbolcz vboxyh nbojup fbovqx ycping qcpujo icpgfw acpsbe scpexm kcpqtu ucpolk mcpahs ecpmda wcpyzi ocpkvq gcpwry zdqjoh rdqvkp jdqhgx bdqtcf tdqfyn ldqruv vdqpml ndqbit fdqneb xdqzaj pdqlwr hdqxsz aerkpi serwlq kerihy cerudg uergzo mersvw werqnm oercju gerofc yerabk qermxs ieryta bfslqj tfsxmr lfsjiz dfsveh vfshap nfstwx xfsron pfsdkv hfspgd zfsbcl rfsnyt jfszub cgtmrk ugtyns mgtkja egtwfi wgtibq ogtuxy ygtspo qgtelw igtqhe agtcdm sgtozu kgtavc dhunsl vhuzot nhulkb fhuxgj xhujcr phuvyz zhutqp rhufmx jhurif bhuden thupav lhubwd eivotm wivapu oivmlc givyhk yivkds qivwza aivurq sivgny kivsjg civefo uivqbw mivcxe fjwpun xjwbqv pjwnmd hjwzil zjwlet rjwxab bjwvsr tjwhoz ljwtkh djwfgp vjwrcx njwdyf gkxqvo ykxcrw qkxone ikxajm akxmfu skxybc ckxwts ukxipa mkxuli ekxghq wkxsdy okxezg hlyrwp zlydsx rlypof jlybkn blyngv tlyzcd dlyxut vlyjqb nlyvmj flyhir xlytez plyfah imzsxq amzety smzqpg kmzclo cmzohw umzade emzyvu wmzkrc omzwnk gmzijs ymzufa qmzgbi jnatyr bnafuz tnarqh lnadmp dnapix vnabef fnazwv xnalsd pnaxol hnajkt znavgb rnahcj kobuzs cobgva uobsri mobenq eobqjy wobcfg gobaxw yobmte qobypm iobklu aobwhc sobidk lpcvat dpchwb vpctsj npcfor fpcrkz xpcdgh hpcbyx zpcnuf rpczqn jpclmv bpcxid tpcjel mqdwbu eqdixc wqdutk oqdgps gqdsla yqdehi iqdczy aqdovg sqdaro kqdmnw cqdyje uqdkfm nrexcv frejyd xrevul prehqt hretmb zrefij jredaz brepwh trebsp lrenox drezkf vrelgn osfydw gsfkze ysfwvm qsfiru isfunc asfgjk ksfeba csfqxi usfctq msfopy esfalg wsfmho ptgzex htglaf ztgxwn rtgjsv jtgvod btghkl ltgfcb dtgryj vtgdur ntgpqz ftgbmh xtgnip quhafy iuhmbg auhyxo suhktw kuhwpe cuhilm muhgdc euhszk wuhevs ouhqra guhcni yuhojq rvibgz jvinch bvizyp tvilux lvixqf dvijmn nvihed fvital xvifwt pvirsb hvidoj zvipkr swjcha kwjodi cwjazq uwjmvy mwjyrg ewjkno owjife gwjubm ywjgxu qwjstc iwjepk awjqls txkdib lxkpej dxkbar vxknwz nxkzsh fxklop pxkjgf hxkvcn zxkhyv rxktud jxkfql bxkrmt uylejc mylqfk eylcbs wyloxa oylati gylmpq qylkhg iylwdo aylizw syluve kylgrm cylsnu vzmfkd nzmrgl fzmdct xzmpyb pzmbuj hzmnqr rzmlih jzmxep bzmjax tzmvwf lzmhsn dzmtov wangle oanshm ganedu yanqzc qancvk ianors sanmji kanyfq cankby uanwxg manito eanupw

The decryption function is

where a - 1 is the modular multiplicative inverse of a modulo m. I.e., it satisfies the equation

The multiplicative inverse of a only exists if a and m are coprime. Hence without the restriction on a decryption might not be possible. It can be shown as follows that decryption function is the inverse of the encryption function,

ROT13 Cipher
Applying ROT13 to a piece of text merely requires examining its alphabetic characters and replacing each one by the letter 13 places further along in the alphabet, wrapping back to the beginning if necessary. A becomes N, B becomes O, and so on up to M, which becomes Z, then the sequence continues at the beginning of the alphabet: N becomes A, O becomes B, and so on to Z, which becomes M. Only those letters which occur in the English alphabet are affected; numbers, symbols, whitespace, and all other characters are left unchanged. Because there are 26 letters in the English alphabet and 26 = 2 * 13, the ROT13 function is its own inverse:

ROT13(ROT13(x)) = x for any basic Latin-alphabet text x

An example plaintext to ciphertext using ROT13:

 Plain: wangle Cipher: jnatyr

Polybius Square

A Polybius Square is a table that allows someone to translate letters into numbers. To give a small level of encryption, this table can be randomized and shared with the recipient. In order to fit the 26 letters of the alphabet into the 25 spots created by the table, the letters i and j are usually combined.
1 2 3 4 5
1 A B C D E
2 F G H I/J K
3 L M N O P
4 Q R S T U
5 V W X Y Z

Basic Form:
 Plain: wangle Cipher: 251133221351

Extended Methods:
Method #1

Plaintext: wangle
 method variations: bfsmqk glxrvp mqcwau rvhbfz

Method #2
Bifid cipher
The message is converted to its coordinates in the usual manner, but they are written vertically beneath:
```w a n g l e
2 1 3 2 1 5
5 1 3 2 3 1 ```
They are then read out in rows:
213215513231
Then divided up into pairs again, and the pairs turned back into letters using the square:
 Plain: wangle Cipher: bhvehc

Method #3

Plaintext: wangle
 method variations: elhbxf lhbxfe hbxfel bxfelh xfelhb felhbx

Permutation Cipher
In classical cryptography, a permutation cipher is a transposition cipher in which the key is a permutation. To apply a cipher, a random permutation of size E is generated (the larger the value of E the more secure the cipher). The plaintext is then broken into segments of size E and the letters within that segment are permuted according to this key.
In theory, any transposition cipher can be viewed as a permutation cipher where E is equal to the length of the plaintext; this is too cumbersome a generalisation to use in actual practice, however.
The idea behind a permutation cipher is to keep the plaintext characters unchanged, butalter their positions by rearrangement using a permutation
This cipher is defined as:
Let m be a positive integer, and K consist of all permutations of {1,...,m}
For a key (permutation) , define:
The encryption function
The decryption function
A small example, assuming m = 6, and the key is the permutation :

The first row is the value of i, and the second row is the corresponding value of (i)
The inverse permutation, is constructed by interchanging the two rows, andrearranging the columns so that the first row is in increasing order, Therefore, is:

Total variation formula:

e = 2,718281828 , n - plaintext length

Plaintext: wangle

 all 720 cipher variations:
 wangle wangel wanlge wanleg wanelg wanegl wagnle wagnel waglne waglen wageln wagenl walgne walgen walnge walneg waleng walegn waegln waegnl waelgn waelng waenlg waengl wnagle wnagel wnalge wnaleg wnaelg wnaegl wngale wngael wnglae wnglea wngela wngeal wnlgae wnlgea wnlage wnlaeg wnleag wnlega wnegla wnegal wnelga wnelag wnealg wneagl wgnale wgnael wgnlae wgnlea wgnela wgneal wganle wganel wgalne wgalen wgaeln wgaenl wglane wglaen wglnae wglnea wglena wglean wgealn wgeanl wgelan wgelna wgenla wgenal wlngae wlngea wlnage wlnaeg wlneag wlnega wlgnae wlgnea wlgane wlgaen wlgean wlgena wlagne wlagen wlange wlaneg wlaeng wlaegn wlegan wlegna wleagn wleang wlenag wlenga wengla wengal wenlga wenlag wenalg wenagl wegnla wegnal weglna weglan wegaln weganl welgna welgan welnga welnag welang welagn weagln weagnl wealgn wealng weanlg weangl awngle awngel awnlge awnleg awnelg awnegl awgnle awgnel awglne awglen awgeln awgenl awlgne awlgen awlnge awlneg awleng awlegn awegln awegnl awelgn awelng awenlg awengl anwgle anwgel anwlge anwleg anwelg anwegl angwle angwel anglwe anglew angelw angewl anlgwe anlgew anlwge anlweg anlewg anlegw aneglw anegwl anelgw anelwg anewlg anewgl agnwle agnwel agnlwe agnlew agnelw agnewl agwnle agwnel agwlne agwlen agweln agwenl aglwne aglwen aglnwe aglnew aglenw aglewn agewln agewnl agelwn agelnw agenlw agenwl alngwe alngew alnwge alnweg alnewg alnegw algnwe algnew algwne algwen algewn algenw alwgne alwgen alwnge alwneg alweng alwegn alegwn alegnw alewgn alewng alenwg alengw aenglw aengwl aenlgw aenlwg aenwlg aenwgl aegnlw aegnwl aeglnw aeglwn aegwln aegwnl aelgnw aelgwn aelngw aelnwg aelwng aelwgn aewgln aewgnl aewlgn aewlng aewnlg aewngl nawgle nawgel nawlge nawleg nawelg nawegl nagwle nagwel naglwe naglew nagelw nagewl nalgwe nalgew nalwge nalweg nalewg nalegw naeglw naegwl naelgw naelwg naewlg naewgl nwagle nwagel nwalge nwaleg nwaelg nwaegl nwgale nwgael nwglae nwglea nwgela nwgeal nwlgae nwlgea nwlage nwlaeg nwleag nwlega nwegla nwegal nwelga nwelag nwealg nweagl ngwale ngwael ngwlae ngwlea ngwela ngweal ngawle ngawel ngalwe ngalew ngaelw ngaewl nglawe nglaew nglwae nglwea nglewa ngleaw ngealw ngeawl ngelaw ngelwa ngewla ngewal nlwgae nlwgea nlwage nlwaeg nlweag nlwega nlgwae nlgwea nlgawe nlgaew nlgeaw nlgewa nlagwe nlagew nlawge nlaweg nlaewg nlaegw nlegaw nlegwa nleagw nleawg nlewag nlewga newgla newgal newlga newlag newalg newagl negwla negwal neglwa neglaw negalw negawl nelgwa nelgaw nelwga nelwag nelawg nelagw neaglw neagwl nealgw nealwg neawlg neawgl ganwle ganwel ganlwe ganlew ganelw ganewl gawnle gawnel gawlne gawlen gaweln gawenl galwne galwen galnwe galnew galenw galewn gaewln gaewnl gaelwn gaelnw gaenlw gaenwl gnawle gnawel gnalwe gnalew gnaelw gnaewl gnwale gnwael gnwlae gnwlea gnwela gnweal gnlwae gnlwea gnlawe gnlaew gnleaw gnlewa gnewla gnewal gnelwa gnelaw gnealw gneawl gwnale gwnael gwnlae gwnlea gwnela gwneal gwanle gwanel gwalne gwalen gwaeln gwaenl gwlane gwlaen gwlnae gwlnea gwlena gwlean gwealn gweanl gwelan gwelna gwenla gwenal glnwae glnwea glnawe glnaew glneaw glnewa glwnae glwnea glwane glwaen glwean glwena glawne glawen glanwe glanew glaenw glaewn glewan glewna gleawn gleanw glenaw glenwa genwla genwal genlwa genlaw genalw genawl gewnla gewnal gewlna gewlan gewaln gewanl gelwna gelwan gelnwa gelnaw gelanw gelawn geawln geawnl gealwn gealnw geanlw geanwl langwe langew lanwge lanweg lanewg lanegw lagnwe lagnew lagwne lagwen lagewn lagenw lawgne lawgen lawnge lawneg laweng lawegn laegwn laegnw laewgn laewng laenwg laengw lnagwe lnagew lnawge lnaweg lnaewg lnaegw lngawe lngaew lngwae lngwea lngewa lngeaw lnwgae lnwgea lnwage lnwaeg lnweag lnwega lnegwa lnegaw lnewga lnewag lneawg lneagw lgnawe lgnaew lgnwae lgnwea lgnewa lgneaw lganwe lganew lgawne lgawen lgaewn lgaenw lgwane lgwaen lgwnae lgwnea lgwena lgwean lgeawn lgeanw lgewan lgewna lgenwa lgenaw lwngae lwngea lwnage lwnaeg lwneag lwnega lwgnae lwgnea lwgane lwgaen lwgean lwgena lwagne lwagen lwange lwaneg lwaeng lwaegn lwegan lwegna lweagn lweang lwenag lwenga lengwa lengaw lenwga lenwag lenawg lenagw legnwa legnaw legwna legwan legawn leganw lewgna lewgan lewnga lewnag lewang lewagn leagwn leagnw leawgn leawng leanwg leangw eanglw eangwl eanlgw eanlwg eanwlg eanwgl eagnlw eagnwl eaglnw eaglwn eagwln eagwnl ealgnw ealgwn ealngw ealnwg ealwng ealwgn eawgln eawgnl eawlgn eawlng eawnlg eawngl enaglw enagwl enalgw enalwg enawlg enawgl engalw engawl englaw englwa engwla engwal enlgaw enlgwa enlagw enlawg enlwag enlwga enwgla enwgal enwlga enwlag enwalg enwagl egnalw egnawl egnlaw egnlwa egnwla egnwal eganlw eganwl egalnw egalwn egawln egawnl eglanw eglawn eglnaw eglnwa eglwna eglwan egwaln egwanl egwlan egwlna egwnla egwnal elngaw elngwa elnagw elnawg elnwag elnwga elgnaw elgnwa elganw elgawn elgwan elgwna elagnw elagwn elangw elanwg elawng elawgn elwgan elwgna elwagn elwang elwnag elwnga ewngla ewngal ewnlga ewnlag ewnalg ewnagl ewgnla ewgnal ewglna ewglan ewgaln ewganl ewlgna ewlgan ewlnga ewlnag ewlang ewlagn ewagln ewagnl ewalgn ewalng ewanlg ewangl

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History of cryptography